I Beat King Leoric ...BUT

[Kasreyn]

The final boss is Diablo, the Lord of Terror. When you find him, he'll appear with the name "The Dark Lord" visible on him, but it's Diablo all right.

When you beat Diablo (or, as we affectionately call the big pink bastard, "D"), the game you're playing ends, and you get a neato movie. However, you can then create new games with the same character to get more experience and loot!

The only problem is, in Single Player, you can only play on Normal difficulty (you won't even see a difficulty selection screen). Normal difficulty is all well and good, but when you get to around level 26-28, the experience gains from killing things in Normal/Hell get very small. The experience gains are so slow it would take a ridiculous amount of time to get to level 40, and that is the absolute limit in Normal difficulty.

If you want to advance into the character level 30's, you'll need to create a multiplayer character. If you want to play alone, just create null modem games and don't invite anyone to join. I recommend this before you venture onto Battle.net; on Bnet you'll have to deal with a lot of strange and dangerous people, and it's best to have a good grounding in the actual game first. Besides, anything below level 20 is usually considered "low" level, and you're not considered high level until you reach your 40's. Of course, the higher difficulty levels provide added challenge for such powerful characters. Give it a try!

Good luck,

-Kasreyn